An EMS‐induced wheat mutant restoring fertility against photoperiod‐sensitive cytoplasmic male sterility

Abstract

Triticum aestivum cv. ‘Norin 26’ with Aegilops crassa cytoplasm shows photoperiod‐sensitive cytoplasmic male sterility (PCMS). This alloplasmic line is almost completely male‐sterile under long‐day conditions (≥ 15h), but highly male‐fertile under short‐day conditions (≤ 14.5h). To obtain male—fertile mutants against PCMS, seeds of the alloplasmic line were treated with ethyl methane sulfonate (EMS). The M3 generation was evaluated for PCMS expression, and one fertility‐restoring (FR‐mutant) line showing high male fertility under the long‐day conditions was selected. Reciprocal F, hybrids between the FR‐mutant and the alloplasmic ‘Norin 26’ showed male sterility under the long‐day conditions, and continuous segregation with respect to the degree of fertility restoration occurred in their F2 generations. These results indicate that multiple recessive mutations with minor effects, induced in the nuclear genome, are involved in the fertility restoration. In fact, no restriction‐fragment‐length polymorphisms of mitochondrial DNA between the FR‐mutant and the alloplasmic ‘Norin 26’ are found.